The present invention relates to wood burners, and in particular, to a burner used in burning waste wood to heat circulating air.
It is conventional in wood-processing plants to use waste wood particles as a source of fuel in heating the air circulating within a wood-products dryer. A conventional type of wood burner used in this setting includes a combustion chamber lined with refractory brick, with the walls of the chamber having a fuel-infeed opening through which fuel is introduced, and multiple openings through which air is injected under pressure. During operation, intense heat and turbulence generated near the chamber's brick walls produce excessive wear on the brick. Typically, the brick must be replaced every six months or so, which is both expensive and time consuming.
A more recent type of wood burner includes a combustion chamber which is surrounded by a circulating-water jacket. A number of problems are associated with this type of burner--among them, that a significant portion of the fuel is used in heating the circulating water, and that, absent any provision for confining combustion to the core region of the chamber, the sides of the chamber are subjected to metal-destructive temperatures. Furthermore, the sides of the chamber and the surrounding water jacket form a sealed unit which is relatively expensive to replace.
One important object of the present invention is to provide a wood burner for burning wood particles or the like, wherein combustion is confined primarily to a core region of the combustion chamber, away from the side wall thereof.
Another object of the invention is to provide a wood burner in which the side wall of the combustion chamber is cooled, and circulated air is preheated, as such air passes into the combustion chamber from the outside.
Yet another object of the invention is to provide a wood burner having an easily replaceable liner forming the side wall of the combustion chamber.
The present invention in wood burning apparatus includes an upright housing containing a removable metal liner, the inner wall of which form the side wall of the burner's combustion chamber, and upper and lower open ends of which form fuel-infeed and heated-gas discharge openings, respectively. A top plate detachably secured to the upper end of the housing provides access to the liner, whereby the same may be easily replaced. The liner is provided with a plurality of tuyeres through which pressurized air can be directed into the chamber, substantially tangentially to the inner wall thereof. An upright, perforated intermediate wall disposed between the housing and the liner forms therewith outer and inner gas-receiving spaces, respectively. Air injected into the outer gas-receiving space passes into the inner gas-receiving space, forming therein a layer of pressurized air surrounding the liner. This air is directed into the chamber, through the liner's tuyeres, to set up within the chamber a vortexing gas which is dischargeable through the gas discharge opening.
Also disclosed herein is a fuel dispersion chamber mounted on the burner's top plate and communicating with the fuel-inlet opening. Wood particles injected into this chamber form a vortex therein, whereby the particles are well-dispersed as they descend into the combustion chamber.
These and other objects and features of the present invention will become more fully apparent when read in connection with the following detailed description of a preferred embodiment of the invention and the accompanying drawings.